Roaster system



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, ROASTER SYSTEM Filed March 21, 1939 2 Sheets-Sheet l r/ i ljkl l e, az

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April 13, 1943- M. D. WOODRUFF ROASTER SYSTEM 2 Sheets-Sheet 2 FiledMarch 21, 1939 such batch roasting and Y Patented Apr'. 13, 1943 MauriceD. Woodruff, S

to The Bauer Brothers Ohio, a corporation of O pringlield, Ohio,assignor Company,

Springfield, hio

Application March 21, 1939, Serial No. 263,261

Claims.

This invention primarily pertains to a. batch roaster for peanuts,coffee, cereals, and analogous products, and more particularly to anautomatic thermally responsive regulatory and signal system and methodof operation for control of color and lavor of the treated materials.The invention is capable, however, of being readily adapted forindustrial purposes for heat treatment of small manufactured parts, orfor other analogous operations. j

For illustrative purpose, but without intention of unduly limiting thescope or application of the invention,y it is herein described in itsrelation to treatment of peanuts for commercial manufacture of peanutbutter. The retail trade is quite critical of the color and taste ofpeanut butter, and requires that the product made from time to timeshall be of uniform shade and flavor. The particular shade of color ofthe roasted peanuts and the flavor of butter manufactured therefrom aredirectly dependent upon the roast-v ing conditions and the extentto'which the roast-l ingoperation is continued.

Heretofore, the batch method of roasting peanuts has necessitated expertsupervision of a skilled operator who knows from experienceapproximately'the requiredtime for properly roasting the nuts underdifferent conditions. It is the practice, however', for such expertoperator to take frequent samples for examination as to color as theroasting operation approaches completion. Being a matter of personaljudgment,

good eyesight and keen appreciation of color values, much diculty hasbeen experienced in maintaining' uniform color and flavor of successivebatches. Even under careful observation, occasional batches are ruinedby the best operators through too little or too long roasting. Too longroasting of the nuts gives to the butter made therefrom a dark,unpleasing color and a strong flavor of being slightly burned. To thecontrary,

too little roasting will fail to develop either the color or flavor. Thebutter therefrom will possess a disagreeable raw tasteand pale color.The roasting time is quite critical. Frequently, a time variationr of aslittle as thirty seconds will eiect a pronounced difference of color andiiavor.

There vare several variable factors whichalect determine the time periodfor properroasting. The temperature of the nuts entering the roaster mayvary as much as thirty (30) degrees or more from a storage temperatureof approximately 90 to 60 F. in winter, which therefore necessitatesgreater or less Warming time. Likewise, a differupon temperature.

F. in summer ence of one degree of moisture content of the nuts whenentering the roaster may necessitate a difference of thirty (30) secondsin the roasting period, which, as stated, may be sufcient to spoil theentire batch for commercial butter making. Other variables which affectthe roasting period and finished result, and therefore to 'beconsidered, are fluctuations of'fuel gas pressure and resultingvariation of roasting temperature, variation of air drafts to which theroaster is subjected and resulting heat radiation, and fluctuatingeffects of chimney drafts on the interior of the roaster. Furthermore,the quantity of nuts containedin a batch is `an important factor indetermining the roasting time period.

lFifteen pounds difference in a batch of three hundred seventy-five(375) pounds as compared with a batch of three hundred sixty (360)pounds will ordinarily cause a' difference of thirty (30) seconds in therequiredroasting time. Also, the relative proportions of mixture of nutsof difierent character or grade, as of Spanish and Virginia nuts, willalso directly affect the roasting time. It is, therefore, highlyimportant that the roasting period be accurately determined andcontrolled as to time and temperature, much more closely than the humanfactor will permit. It has been found that color is directly dependentIt has been found that a final temperature of approximately 275 degreesFahrenheit produces a color most acceptable to the trade. Numerousattempts have been made to control the result by taking temperaturewithin the roasting cylinder, but merely taking the air temperaturewithin. the cylinder is not reliable. The roasting operation issuciently critical that the actual temperature of the nuts themselves isthe important factor. Also, to take the temperature in a more or lessrapidly moving portion of the mass is not sumciently accurate, and theintroduction of a thermometer or other thermal responsive device willinterrupt the flow of nuts and cause the formation of an air pocket, thetemperature of which will be registered and thus give a false reading. x

To insure uniform roasting and maintenance of established standards o fcolor and flavor of the nished product, the present invention includesthe herein described vmethod of utilizing the temperature reaction froma zone of minimum disturbance in the mass where the'material conformsclosely to the thermometer bulb or responsive portion of the-thermalelement, which temperature response is utilized to indicate the progressof the roasting operation and control the heat supply or perform othersteps in the operation.

The object of the present invention is to provide a roasting apparatusof the character described, which may not only be economicallymanufactured, but will be highly eicient in use, uniform in operation,automatic in action, and unlikely to get out of repair.

A further object of the invention is to provide means for accuratelygauging the roasting period while automatically compensating for varyingcontrolling factors.

A further object of the invention is to provide a method of accuratetemperature determination of a mass of roasting nuts or other material.

A further object is to provide an improved temperature controlled signalsystem for automatically indicating the progress of the roastingoperation.

A further object of the invention is to enable the mounting of a controlthermometer in such relation to the mass of roasting material as toafford accurate readings, unaffected by air pockets in the mass orirregular distribution of the material.

A further object of the invention is to provide safety means to protectagainst accidental overheating of the roaster.

A primary object of the invention is to provide an apparatus and methodof operation which will relieve the operator of the necessity forexercise of expert judgment and which will enable automatic,substantially fool-proof control of the operations and thereby insureuniformity of the product.

With the above primary and other incidental objects in view as will morefully appear in the specification, the invention consists of thefeatures of construction, the parts and combinations thereof, and themode of operation, or their equivalents as hereinafter described and setforth in the claims.

In the drawings, wherein is shown the preferred, but obviously notnecessarily the only form of embodiment of the invention, Fig. 1 is aside elevation partly broken away of an assembled roasting apparatusshowing placement of the thermally responsive element.

Fig. 2 is an end elevation thereof, also partly broken away toillustrate the relation of the control thermometer bulb with the mass ofmaterial being operated upon.

Fig. 3 is an electrical diagram of the signal control system andautomatic protective means.

Fig. 4 is a detail view of a thermo-electric regulator wherein anenclosed column of mercury closes a series of contacts successively.

Like parts are indicated by similar characters of reference throughoutthe several views.

While, as before mentioned, the present apparatus and method isespecially adapted for peanut roasting, it is to be understood that itis not limited thereto, but is applicable to conditioning of othermaterials including coffee, cereals and the like, `and also for heattreatment o f manufactured articles.

In the drawings there is shown a roaster wherein a suitable retort orhousing I supported on legs 2 encloses a rotary drum 3 mounted thereinfor rotation about a horizontal axis.` The rotary drum 3 is heated by asuitable burner, either exteriorly or interiorly of the drum. Thepreferable heater means comprises gas burners 4 of the radiant type,substantially axially disposed interiorly of the drum and supplied withfuel gas through the air-gas mixer conduit 5. Fumes, vapors and volatilesubstances released from the material during roasting are drawn from thedrum through a flue 6, communicating with the interior of the drumandsurrounding the fuel supply conduit 5.

The nuts, or other material operated upon, are supplied to the drum froman elevated funnel shaped hopper 1, having at its lower end a manuallyoperated cut-off slide or gate controlled by the hand lever 8.Interiorly the rotary drum 3 is provided with a double series ofreversely arranged helically disposed vanes, which as the drum rotatestend to divert the nuts first in one direction and then in the other toinsure thorough and uniform agitation and distribution of the nuts inthe drum. By rotation of the drum, the nuts are carried upwardly untilthe mass of nuts 9 assumes an oblique position progressively projectedbeyond the angle of repose whereby the uppermost nuts continue todescend by gravity to the lower margin of the mass. As shown by theseries of arrows in Fig. 2 of the drawings, the nuts progressivelytraverse a circuitous path in which they ascend through an arcuate pathcontiguous to the circumferential wall of the drum and descend throughan inclined straight path along the chord of their arcuate ascendingpath.

The nuts interiorly of the mass move less rapidly in concentric paths ofever .decreasing extent. Due to the reversely inclined deflector varies,the nuts are continuously diverted from one course to another, the innernuts of the mass being deflected outwardly and the exterior nuts aredirected inwardly. There is, however, at the center or vortex of themass substantially concentric with the paths of travel of the nuts, azone l0 of comparative quiet or minimum disturbance. While no nuts comepermanently to rest in such zone, there is not such flow as would belikely to form air pockets, and the temperature in the vortex zone isfairly indicative of the temperature of the entire mass.

Therefore, this vortex of the circulating mass of nuts has been adoptedfor present temperature control purposes. Supported upon and projectingradially from the axially disposed heater means is a thermal elementsupport and guard l I, which extendsy into the mass of nuts and carriesat the critical point, to Wit, the vortex of the mass, a thermallyresponsive element I2. In the drawings this is shown as athermo-electric device comprising a high temperature thermometer havingelectrical contacts closed by the thermal fluid at predeterminedtemperatures for control of a signal and regulatory system. However, itisto be understod that various forms of thermally responsive means maybe employed, as for example, a Peltier thermo-couple, or a thermostat,or othery thermo-electric means for energizing an electric circuit whena predetermined temperature has been attained.

Even though no electrical control or signal apparatusl is employed, themeans and method hereinbefore described is quite desirable for takingaccurate temperature readings of the .mass of material'during progressof the operations. It has been found that temperature readings takenWithin the drum in the air above the mass of nuts are quite unreliable,and will not enable the close and accurate control of temperature foundessential to proper commercial conditioning of the material. Likewise,Iit is found that if the reading is taken at a.

higher point dicated at ln thel mass where the nuts are moving morerapidly down their inclined path, the obstruction alforded by theinstrument and its mounting which tend to cause the nuts to pile-up onone side and form Van 1air pocket at the lower side thereof, also givesa false temperature indication. It is therefore found that while thenuts circulate about the thermal instrument when positioned at thevortexrof themass, they do so quite evenly without formation 'of airpockets, and that the circulation and agitation of the nuts in the massis sufficient that the temperature of those nuts at the center or vortexof the mass is uniform with those elsewhere in-the mass, and that quiteaccurate determination of temperature of the mass is enabled.

yThe fluctuation of temperature, as determined by a thermo-'electricinstrument I2, may be utilized to control remote signal andregulatingmeans of any desired character. For illustrative purposes, there isdiagrammatically shown in Fig. 3 an electrical system wherein thefluctuation of the thermo-electric .instrument serves to operatedifferent signals toindicate, first that fuel supply valve is open andthe heater means in operation, second a warning that the roastingoperation is approaching completion and a final signal when theoperation is fully completed. In addition thereto, the samethermo-electric instrument and electrical system serves to automaticallyshut oli the fuel supply in event thev oven becomes overheated.Obviously, other signal and regulatory devices may be included in thesystem, under control of the same thermally responsive instrument.

Referring to the electrical diagram Fig. 3, the several signal deviceswhich may be lights or bells, are preferably provided in multiple, oneset being contiguous to the roaster apparatusl and another at someremote supervisory station. The warning signal, nal signal, and heatersignal are shown at I3, I4 and I5 respectively. rl',he thermo-electricinstrument is schematically ini2. The signals are supplied with currentat full voltage, while the several electrically operated switchestherefor are actuated by reduced voltage supplied by a suitable trans--former in the system.

Current is supplied from the service lines through the switch I6 andlines I1a and I1b leading to the primary side of the transformer I8. Acontinuing line I8 leads from the line 11b to a pair of contacts 23 andl22; which are electrically connected with complementary contacts 2| and23 pertaining respectively to the warning signals I3 and final signalsI4, by electrically operated circuit closers 24 and 25. The circuitclosers are illustrated' as of the solenoid type, energized throughlines A2li and 21 respectively from the secondary side of thetransformer I8. The electric switches 24 and 25 are connected throughthe continuing lines 28 and 29 with differently positioned contacts 38and 3I of the thermo-electric control instrument I2 and automaticallyclosed at different temperatures. The thermo-electric control instrumentI2 is in turn connected by a common return line 32 with the oppositeterminal vof the transformer secondary winding, thereby completing thecircuit.

In addition to the electrically operated circuit closers 24 and 25,there is provided a multiple switch 33, one contact 34 of which isconnected through the line 35 with the current supply line I1b. Suchcontact 34 cooperates with a complementary contact 36' to close thecircuit through the line 36 to the heater signal I5. The several signalsI3, I4 and I5 are connected through a common line 31 with the supplyline Ila, thereby completing the several circuits therethrough when therespective circuit closers are actuated.

In addition to the pole 34, the switch 33 has a contact pole 38connected in series with the winding of the switch 33, which onoperation of the switch closes with a contact 39 connected through aline 40 with a thermally closed contact 4I of the thermally responsiveinstrument I2 which, as before stated, is connected through the commonreturn line 32 with the opposite side of the transformer secondaryWinding. The line 48 has therein a 'normally closed stop button contact42 to be manually opened. Connected around this normally closed stopbutton contact 42is a shunt 43, in which is a normally openmanuallyoperable start contact button 44. Opening the stop button 42deenergizes the operator coil of the switch 33 and thereby allows thecontact -38-33 to open. Such switch coil will remain deenergized untilthe start button 44 is momentarily closed to energize the coil of theswitch 33, whereby the contacts 38-39 are again closed to reestablishthe circuit through the switch coil by which they are then held inclosed K relation. The same switch is further provided with a third pole45, which when the switch coil 1s deenergized, closes with a contact 46,and when the switch coil is energized, the pole 45 breaks its contactwith the contact 46 and makes con-4 tact with a second complementarycontact 41.

The switch pole 45 is connected through the line 48 with the secondaryside of the transformer I8. In either position of the switch the contactpole 45 supplies current through alternately the line 49 or the line 5l)to the motor unit 5I, indicated only diagrammatically in Fig. 3. Aswitch 52 associated with the motor 5| serves to open vand close thecircuit through the line 53 to the winding of the multipleswitch 33, theopposite side of which is connected through the line 48 and return line32 to the opposite side of the transformer I8 secondary.

It has been found in practice that the operator can not read the dial ofthe thermometer with suiicient accuracy to obtain perfect control of thecolor. To obtain best results the thermometer is connected through anelectrical system which is capable of making a signal when thetemperature of the material has reached a predetermined point. It hasalso been found advisable to provide a warning signal about secondsbefore the final signal so that the operator will be ready to dischargethe roaster when the final signal occurs.

Briefly stated, the operation is as follows: Closing the start buttonNo. 44 allows an electric current to iiow from the secondary side oftransformer I8, through the solenoid of multiple switch 33, throughlines 43 and 40 to commutator brush 4I and then through line 32 to theopposite side of the secondary of transformer I8. When the solenoidofmultiple switch 33 is venergized, the three contacts, 45, 34 and 38close with their respective contacts 41, 36 and 39.

When contacts 38 and 39 are closed, a circuit is established from thesecondary side of transformer I8 through the solenoid of multiple switch33, through contacts 38, 39, through contact 42, and thence through line40 to the opposite side of the secondary transformer I8 as outlinedabove. When contacts 34 and 36' are closed, a circuit is establishedfrom line` I1b through line 35, through contacts 34, 35', through lamp I5, and is completed when it joins I'Ia. The lamp or signal I5 thenindicates thatl the electrical portion ofthe system is in operation.

When contacts 45, 4I are closed, a .circuit is ,established from thesecondary of transformer I8 through une '4a. through contacts 45, a1,and thence to suitable contacts on the motor operated valve 5I, whichcauses this valve to open and permit the fuel gas to flow through pipe 5to th mixing valve.

-With the roaster in operation, a torch is held under the burners andthe mixing valve is opened. After the burners are lighted, the peanutsare fed'from the hopper 'I to the'in'terior of the roaster, Where theroasting operation commences. Thethermo-electric instrument is soarranged that in about 90 seconds before the completion of the roast,commutator 3D makes .contact with brush 30, establishing a circuit fromthe secondary side of transformer I8 through4 line 26. through solenoid24, through line 28, throughvllne 32 to the opposite side of thesecondary of transformer I8. Energizing this solenoid closes contacts2I,` 24 and 20, allowing-current to flow through the warning signal I3,which warns the operator that the roast is nearly completed.

.When the nal temperature isreached, the commutator 3i' 'has beenrotated by the expansion of the thermal vfluid until it makes contactwith commutator brush 3i. This allows current to flow from the secondaryside of transformer I8,`

through line 2'I, through solenoid 25, through line 29, through 3|, andthence through line 32 to the OpDQSite side of the secondary oftransformer I8. Energizing solenoid closes the contacts 23, 25', 22,which in turn causes signal I4 to operate. The roaster is thenimmediately dis cha'rged, thus completing the cycle.

Should the roaster be allowed to run empty with the burners lighted, theexpansion of the thermal fluid would rotate commutator 4I until thecircuit with commutator brush 4I is broken.

This would disrupt the circuit which energizesthe multiple switch 33,allowing the contacts to open. When in the open position as shown linFig. 3, a circuit is then established from the secondary side oftransformer I8, through line 48, through contacts 45 and 46, throughline 4,9, to suitable contacts in the motor operated valve 5I, whichcauses this valve to clos-e, thus Ashutting off the gas supply andthereby preventing damage to the roaster from overheating. 'Pushing stopbut-- ton 42 interrupts the same circuit and hence pro- Y duces the sameeffect. The-thermo-electric control device may be a simple thermometeras shown in Fig. 4, having relatively spaced electrical contactsprovided in its wall which are successively closed by the expansion ofthe enclosed column of mercury. The preferred thermo-electric member isthat shown in Fig. 3, of the commutatortype, comprising a series ofdiscs mounted for to and-fro oscillatory motion about a common axis.Each disc includes a conductive section and a non-conductive portionengaged by a contact brush or nger riding thereon. The series of discsare oscillated to and fro in accordance with fluctuations of temperatureunder influence of the thermo-electric member I2.

From the above description it will be apparent that there is thusprovided a device of the char acter described possessing the particularfeatures of advantage before enumerated as desirable, but

Awhich obviously is susceptible of modification in 'its form,proportions, detail construction and arprinciple involved rangement ofparts without departing from the or sacrificing any of its advantages.

While in order to comply with the statute, the invention has beendescribed in language more or less specific as to structural features,it is to be understood that the invention is not limited to the specificfeatures shown, but that the means and construction herein disclosedcomprise the preferred form of several modes of putting the inventioninto effect, and the invention is therefore claimed in any of its formsor modifications within the legitimate and valid scope of the ap pendedclaims.

Having thus described my invention, I claim:

1. A roasting apparatus, wherein a mass of peanuts or the like aretumbled in a heated vrotary drum by being carried upwardlycircumferentially of the drum beyond the angle of repose and allowed todescend by gravity through an inclined path disposed as a chord of theirascending path, including a rotary drum and a heater thereforcharacterized by a thermo-electric member positioned at the vortex ofthe mass of nuts and subject to fluctuations of temperature of the mass,a series of electrically operated signal devices exteriorly of therotating drum. an electrical .power circuit for supplying current tosaid signal devices, independently operated switches pertaining to therespective signal de vices, and a series of switch operating electricalcircuits successively`closed by the thermo-electric member forenergizing the signal devices in predetermined sequence in synchronismwith the progress of the roasting operation.

' 2. A roasting apparatus, wherein a mass of peanuts or the like aretumbled in a heated rotary drum by `being carried upwardlycircumferentialy of the drum beyond the angle of repose and allowed todescend by gravity through an inclined path disposedas a chord of theirascending path, including a rotary drum and a heater thereforcharacterized by a thermally responsive member, a support therefor onwhich the thermally responsive member is stationarily positioned atsubstantially the vortex of the moving mass Yof material, and indicatormeans exteriorly of the drum controlled by the thermally responsivemember.

3. The combination with a rotary heated cyl inder, within which va massof material operated upon is tumbled and thereby caused to ow through acircuitous path about a horizontal axis within the mass of material anda heater therefor, of a thermally responsive memberstationarilypositioned within the cylinder at a point of minimumdisturbance within the mass and about which the material is circulated,and multiple signal means exteriorly of the cylinder controlled byfluctuation of the thermally responsive member to successively energizedifferent signal means to indicate predetermined progress of heattreatment lof the material.

4. The combination with a rotary heated drum within .which a mass 0fmaterial operated upon occupying only a segmental portion of the drum istumbled through a circuitous path by being carried upward with therotation of the drum beyond the,angle of stability and allowed todescend along a chord of the occupied segment of the drum and a heatertherefor, of a thermal responsive member locatedin an area of minimumdisturbance substantially at the center 0f such circuitous travel motionof the material mass, and at a point of minimum hindrance thereto, asignal device controlled by the thermal responsive member indicative ofapproach to predetermined temperature, a second signal device controlledby said thermal responsive device in sequence with operation of the rstsignal and indicative of attainment of a predetermined temperature, anda fuel control device operative by the thermal responsive device insequence with the signal devices for limiting the temperature of thedrum toa predetermined maximum degree.

5. In a roasting apparatus of the character described, a rotary heateddrum in which a mass of material operated upon is tumbled through acircuitous path within a segmental portion only of the drum by beingcarried upward through an arcuate path to a point beyond the angle ofrepose and allowed to descend through a chord of such segmental portion,a heater for said drum, an electrothermal member located at the centerof minimum disturbance of said circulating mass, an electrical systemcontrolled `thereby including sequentially operated signal andtemperature limit means including a signal indicative of approach t0 apredetermined roasting temperature, a signal indicative of attainment ofa predetermined roasting temperature and a heating medium control devicefor said drum heater operative to limit the temperature generatedthereby to a predetermined maximum degree, and a succession of contactsin said electrical system pertaining to the respective signals and tothe temperature fuel control device closed in sequence by the thermallyresponsive member.

6. A roasting apparatus, wherein a mass of material is tumbled in aheated rotary drum by being carried upwardly circumferentially of thedrum beyond the angle of repose and allowed to descend by gravitythrough an inclined path disposed as a chord of its ascending path,including a rotary drum and a heater therefor. characterized by athermo-electric member positioned below the axis of the drum andextending into the mass of material at a point in a plane extendinglongitudinally of and passing through the axis of the drum andperpendicular to said path and subject to fluctuations of temperature ofthe mass, an electrically operated relay system responsive to saidthermo-electric member, and signal devices actuated by said relay systemindicating the progress of the roasting operation.

7. In a roasting apparatus,.wherein a mass of material is tumbled in aheated rotary drum by being carried upwardly circumferentially of thedrum beyond the angle of repose and allowed to descend by gravitythrough an inclined path disposed as' a chord of its ascending path,including a rotary drum, characterized by a. thermo-electric memberpositioned below the axis of the drum and extending into the mass ofmaterial at a point in a plane extending longitudinally of and passingthrough the axis of the drum and perpendicular to said path and sub-`iect to fluctuations of temperature of the mass.

-heater means for the drum, an electrically operated fuel control valvetherefor, and an electrical circuit governed by the thermo-electricmember for actuating the fuel control valve.

8. The combination with a rotary heated cylinder, within'which a mass ofmaterial operated upon is carried upwardly circumferentially of thecylinder beyond the angle of repose and allowed to descend by gravitythrough an inclined path disposed as a chord of its ascending path, ofathermally responsive member about which the material is circulatedstationarily positioned within the cylinder at a point below the axis ofthe cylinder and submerged in the mass of material at a point in a planeextending longitudinally of and passing through the axis of Y thecylinder and perpendicular to said inclined path, and heater means forthe cylinder controlled by the thermally responsive member.

9. Theherein described method including the steps of heating a mass ofmobile material and simultaneously revolving the heated mass of mobilematerial in substantially concentric relation with a thermo-responsivedevice disposed substantially at the center of motion of the mass andautomatically controlling the temperature of the revolving mass inaccordance with the fluctuations of said thermo-responsive device` l0..The herein described method including the steps of heating a mass ofmobile material and Vsimultaneously revolving the heated mass of mobilematerial in substantially concentric relation with a thermo-responsivedevice disposed substantially at the vortex of the mass andprogressively signaling exteriorly of the mass different successivethermal conditions occurring thereinl MAURICE D. WOODRUFF.

